The father of a homeless California man allegedly beaten to death by police officers last year has begun legal action against city authorities.

A year to the day since the encounter with six Fullerton police officers that led to Kelly Thomas's death, his father, Ron Thomas, filed a civil lawsuit in Santa Ana superior court.

The six officers involved in the incident, along with two former Fullerton police chiefs, and the city itself were named as defendants in the suit.

Ron Thomas alleged that a combination of heavy-handed restraint, repeated blows and the use of a Taser resulted in his son's death.

Speaking at a press conference Thursday, Thomas, a former Orange County sheriff's deputy, argued the Fullerton police department suffers from a deep-seated "culture of corruption and deliberate indifference." He believes his son's federal and state civil rights were violated.

"There's an atmosphere around Fullerton with the police department that they can get away with anything they want," he said.

The lawsuit does not specify a dollar amount for damages. Kelly Thomas's mother Cathy previously reached a $1m settlement with the city and agreed not to pursue any further claims. The deal did not involve her ex-husband, Ron.

The beating of Kelly Thomas – who had mental health problems – was captured on videotape and digital audio recording devices worn by some of the officers. The officers were responding to a call regarding cars being broken into in the area.

The recordings, along with photos of Kelly's face following the encounter, have fueled outrage among residents, as they appear to depict a confused and increasingly terrified Thomas begging for mercy, until he lost consciousness in a large pool of blood. He repeatedly called out to his father for help.

"Dad, they are killing me!" Thomas could be heard yelling as he lay on the ground, struck over and over with fists, a baton and the butt of a stun gun. Thomas apologized again and again to the officers as they beat him.

"I am sorry, dude, I can't breathe, dude," he said.

Five days after Thomas was beaten and slipped into a coma, he died in a hospital bed. According to the Orange County coroner, the cause of death was asphyxiation resulting from chest compression. The compression was so severe that the 37 year-old's brain was deprived of oxygen and blood from his facial wounds flooded his lungs.

Thomas's death led to protests and vigils in Fullerton, as well as national media attention, and served as referendum on the Fullerton police department and elected officials. Three city council members were ousted by angry residents over a perceived lack of concern, and the chief of police retired. An FBI investigation was launched and criminal charges were filed against two of the six officers involved.

"They're getting ready to fuck you up," the officer said, then pulled a pair of latex gloves onto his hands.

Jay Cicinelli is charged with involuntary manslaughter and assault or battery by a public officer. Cicinelli was recorded saying: "We ran out of options so I got the end of my Taser and I probably… I just smashed his face to hell."

Both officers have pleaded not guilty, maintaining that Thomas's actions led to his death. In May, a judge ordered that they stand trial. They are scheduled to be arraigned on 15 July.